Buttonhole sewing machine



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\nv'enTon May 12, 1931. A. F. CARLSON BUTTONHOLE SEWING MACHINE Filed March 20, 1928 2 Sheets-Sheet lnvenTor. Axd F Cuflson b mwym ATTys.

Patented May 12, 1931 UNITED STATES PATENT OFFICE AXEL F. CARLSON, F CAMBRIDGE, MASSACHUSETTS, ASSIGNOR TO THE REECE BUTTON HOLE MACHINE OOMPAN Y, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE BUTTON HOLE SEWING MACHINE Application filed March 20, 1928.

This invention relates to sewing machines and particularly to the means for so controlling the needle thread during the formation of the first stitches of any sewing operation as to obviate the possibility that the first stitch will be skipped. In sewing machines of that type which are designed to perform a predetermined sewing operation and then come to rest, such for instance as buttonhole sewing machines, it is a more or less common practice to provide means for cutting the upper and under thread when the sewing machine comes to rest at the end of each sewing operation and also to provide means for holding the cut end until the next sewing operation has begun. The upper thread is usually led to the. needle through a tension device and it is the common practice to employ a take-up device which acts on the thread between the tension and the needle and which operates to tighten each stitch as it is formed.

If the full tension is applied to the needle thread when the sewing starts or during the.

formation of the first stitch there is the possibility that the action of the take-up in tightening the first stitch will pull either the under thread or the upper thread back through the work thus causing the first stitch to be dropped or pulled out.

It is one of the objects of my present invention to provide novel means for obviating such a possibility and I accomplish it herein by employing means to release the tension on the upper thread during the formation of the first stitch so that the threads of said stitch will be loosely concatenated and so that the take-up when it operates will draw thread from the source of supply through the released tension rather than to pull the thread back through the first stitch. As the second stitch is being formed the tension is again applied to the needle thread and the action of the take-up in tightening the second stitch will also serve to tighten the loosely concatenated thread of the first stitch.

With my improvements the first stitch of the buttonhole or other seam will always be properly formed without danger of being pulled out by the action of the take-up.

In order to give an understanding of the Serial No. 263,103.

invention I have illustrated in the drawings a selected embodiment thereof which will now be described after which the novel features will be pointed out in the appended claims.

Fig. 1 is a side view of a sewing machine embodying my invention;

Fig. 2 is a top plan view of Fig. 1;

Fig. 3 is a View illustrating the position of the parts as the tension is restored;

Fig. 4 is a sectional view through the tension device on substantially the line 44, Fi 1;

Fig. 5 is a section on the line 5-5, Fig. 4.

I have chosen herein to illustrate my invention as it may be applied to a sewing machine having the general constructional features illustrated in my Patent No. 1,771,670, dated July 29, 1930.

The frame of the machine is indicated at 1 and it is provided with the work-supporting arm 2 on which the work is held during the sewing operation by suitable work clamps 3. The frame also is provided with the overhanging arm 4 in which is mounted a vertically-reciprocating needle bar 5 carrying the needle 6 which controls the needle or upper thread 7. This needle thread 7 which is drawn from a suitable source of supply is taken through a secondary tension 75 which applies a light tension thereto and thence through the usual main tension 11 which applies a relatively heavy tension thereto. From the tension 11 the thread passes through guide eyes 10 to the take-up arm 9 and from the take-up arm 9 it passes through the guide 8 to the needle 6, all as usual in sewing machines of this type.

The needle receives its vertical reciprocation from a shaft 41 extending longitudinally of the arm 4, said shaft being geared to and driven by the driving shaft 12, all as usual in sewing machines. In addition to its reciprocating motion the needle has a lateral jogging motion as usual in sewing machines, such motion being derived from the switch cam 42 which is carried by the shaft 41.

The needle bar reciprocates in a vibrating frame 47 which is pivotally mounted to the head 4 at 50 and said frame is connected by a link 46 to a swinging arm 43 pivotally mounted at 51. The swinging arm 43 has a pin or follower 52 depending therefrom which operates in the roove in the switch cam 42 on the shaft 41 all as usual, the construction being such that the arm 43 makes a complete ibration for each two rotations of the shaft 41. The connection between the link 46 and the swinging arm 48 is an adjustable one so as to provide for varying the amplitude of movement of the swinging frame 47, said arm 43 being provided with the curved slot 45 in which the end of the link 46 is adjustable, said link being held in its adjusted position by the clamping screw 44.

The operation of the switch cam is so familiar to those skilled in the art that it is not necessary to further describe it.

The work clamps 3 have associated therewith a thread gripper 13 and a thread cutter 14, both of which are constructed and operated in the manner similar to the gripper and thread cutter illustrated in my above-mentioned Patent No. 1,771,670. This gripper and thread cutter are actuated at the proper time in the sewing cycle from a cam 15 which is loosely mounted on a cam shaft 16, the latter being continuously driven from the driving pulley 56.

The cam 15 is normally idle during the sewing operation but when the sewing mechanism is brought to rest said cam is clutched to the shaft 16 and makes one revolution and during this revolution it operates an arm 17 fast on a shaft 18, which shaft has another arm 19 fast thereto that is connected by the link 20 to means similar to that shown in my above-mentioned patent for operating the grirpper 13 and the cutter 14.

nasmuch as the present invention does not relate to the gripper 13 and cutter 14 nor the particular means by which these parts are operated and inasmuch as said parts are shown in detail in my above-mentioned patent, I have not thought it necessary to illustrate said mechanism herein. For the purpose of the present invention it is sufficient to understand that at the end of the sewing operation the normally idle cam 15 is clutched to the shaft 16 and is given one rotation and is then automatically unclutched therefrom and during such rotation it actuates the gripper and thread cutter. It will be understood that this operation of the gripper and thread cutter occurs before the work clamps are raised and while the work is still clamped.

The device illustrated in my above-merrtioned Patent No. 1,771,670 is provided with a pull-off having for its purpose to pull a length of needle thread through the tension when the sewing operation has been completed and it is further provided with means for relieving the tension on the needle thread at the time that the pull-off operates.

The machine herein illustrated is also provided with a similar tension release. The tension comprises two friction disks 21, 22 which are mounted on a stud 23 carried by the overhanging arm 4. The tension disk 22 is engaged by another disk 61 which is acted on by the spring 24, the latter being confined between the disk 61 and the thumb piece 25 that is screw threaded to the stud 23, this being a. common form of thread tension device.

The stud 23 is shown as provided with a slot 26 extending longitudinally thereof and the disk 61 is formed with a bridge piece 62 spanning the opening therein through which the stud ;3 extends, said bridge piece extending through the slot 26.

Situated axially of the stud. 23 is a push pin 27 which is adapted to en the bridge portion 62 of the disk (31 so that when the push pin 27 is moved to the right Fi 4 the disk 61 will be moved axially of the stud thus compressing the sprin 24 and relieving the tension on the thread. The push pin 27 is actuated at tl e proper time by means of a sliding actuator 28 in the form of a rod that is carried by suitable bearings 29. This rod is normally held in its rearward or retracted postion Sl1OW1 by dotted lines Fig. 2 by means of a sprng 80 which surrounds the rod and is interposed between the bearing 29 and a collar 31 on the red. A second col.- lar 6O co-opcrates with the bearing 29 to limit the spring-impelled movement of said rod.

The actuating rod 28 is provided with a depresson 32 which is so situated that when the rod is in its normal retracted position the depression comes opposite the push pin and the latter occupies said depression as shown in 4. Under these circumstances the spring 24 is free to apply the requisite tension to the thread. This is the positon of the parts while the edge stitches of the buttonhole are being formed except at the very start.

It "ill be olrservcd from Fig. 4 that if the rod 28 moved downwardly in said figure, which is the equimlent of moving the rod from the dotted to the full line position Fig. 2, the rain face of the depression 32 will er s the end of the push pin 27 and will force the same axially of the stud 23 thereby forcing the disl (31 outwardly and rclievi the tea-Ion disk of the pressure of the spring 24 and thus relieving the tension on the needle thread.

In accorcancc with my 'iresent invention 0 is given its operative the actuator rod 2o movement from the dotted to the full line position, Fig. 2 at the time that the sewing machine is brought to rest so that the chine will come to rest with the tension on the upper thread relieved.

i a rock shaft which has fast thereon two arms 3: The arm is adapted to engage a c ollar 66 which isloosely mounted on the rod 28 in the rear of the collar 31. When the actuating rod 28 is in its normal position shown in dotted lines Figs. 1 and 2 the collar 31 abuts against the collar 66.

The arm 36 isadapted to be engaged by a cam 67 on the shaft 16, said cam 67 rocking the shaft 34 and thereby swinging the arm 35 to the left Fig. 1. It will be remembered that during the sewing on the buttonhole the rod 28 is in the dotted line position Fig. 1 with the collar 31 against the collar 66.

The cams 15 and 67 are normally idle during'the sewing operation but when the buttonhole or other seam is finished said cams are clutched to the shaft 16 and are given one rotation all as described in my abovementioned patent. During this rotation, which is in the direction of the arrow Fig. 1, the shaft cam 67 engages the lever 36 and rocks the shaft 34 thereby moving the lever 35 to the left F 1. This movement operates through the collars 66 and 31 to move the actuator 28 to the left thereby to effect the release of the tension 11 on the needle thread 7.

In the device shown in the above-men tioned patent this release of the tension is momentary only to permit the pull-off to draw a length of needle thread through the tension suficient to form the first stitch of the next sewing operation and in said device as soon as the cam 67 has passed out from under the arm 36 the tension is restored so that the machine comes to rest with the tension on the upper thread.

In my present invention I have provided means for maintaining the tension released while the sewing machine is stopped and until after the first stitch has been formed during the next succeeding sewing operation. This is herein accomplished by providing a latch mechanism which automatically latches the actuator 28 in its forward or operative position, said latch being released automatically during the formation of the second stitch. This latch is shown at 37 and it is pivoted to the arm 4 at 38. The actuator rod 28 is provided with a lug or projection 39 with which the latch co-operates to hold the actuator 28 in its operative position.

During the sewing of the buttonhole the parts are in the position shown in Fig. 3, the actuator 28 being in its rearward or retracted position and the latch being disengaged from the projection 39. When the sewing operation has beencompletedand the machine comes to rest the actuator 28 is moved forwardly or to the left in the position shown in Fig. 1 and as this occurs the latch 37, which is acted on by a spring 40, will automatically engage the projection 39 and thus lock the actuator in its forward position with the spring 30 under compression. Thus when the sewing machine comes to rest the actuator is locked in its forward position and the tension 11 is released so that said tension 11 remains in its released condition while the machine is at rest.

Means are provided whereby after the first stitch of the next succeeding operation has been formed the latch 37 will be automatically released thereby permitting the actuator 28 to return to its normal position under the influence of the spring 30, with the result that the tension 11 will be again applied to the needle thread.

It will, therefore, be seen that with this invention the tension on the needle thread is released at the end of the sewing operation and is held released until after the first stitch is formed on the next succeeding sewing operation so that the first stitch of each sewing operation is made with the needle thread free of the tension 11.

The release of the latch 37 and the application of the tension to the needle thread is accomplished through the operation of the needle-jogging mechanism.

The vibrating arm 43 of the needle-jogging mechanism is provided with an extension or finger 48 which co-operates with an upstanding portion 49 of the latch 37 to release the latter. During the sewing operation and when the actuator 28 is in its retracted position the upstanding portion 49 of the latch will be situated out of the path of movement of the finger 48, said latch being held in this position by the extension 59 thereof resting upon the projection 39, as seen in Fig. 3. When the actuator 28 is moved to the left into the position shown in Fig. 1 by the operation of the cam 67 and the latch is carried into operative engagement with said projection as shown in Fig. 1 the upper end of the upstanding portion 49 is brought into the path of movement of the finger 48.

The stop motion is so designed that the machine will be brought to rest with the vibrating arm 43 in a position midway between the full and dotted line positions shown in Fig. 2, and when the machine is started said arm 43 and finger 48 are moved to the right into the full line position Fig. 2 and then moved to the left to the dotted line position. During this movement of the arm 43 the first stitch will be formed and as the second stitch is being formed the finger 48 is carried into the dot-ted line position, Fig. 2 in which position it engages the upstanding end 49 of the latch and trips the latter so that the spring 30 will return the actuator 28 to its normal position and the tension 11 will be applied to the needle thread.

With this invention, therefore, the sewing machine is stopped at the end of each sew- .i

ing operation with the tension 11 released and said tension will remain in its released condition until after the first stitch of the next succeeding sewing operation has been perfomed, the first stitch being made witha loose tension so that the threads will be loosely concatenated. Because of this fact there will be no danger that the threads of the first stitch will be pulled out by the action of the take-up as might be the case if the tension 11 were applied while the take-up was operating to tighten the first stitch.

During the formation of the second stitch the latch 37 is released as above described and the tension 11 is applied to the needle thread and, therefore, when the take-up operates to tighten the second stitch the needle thread is subjected to the full tension 11. As a result the second stitch will be tightened in usual manner and in doing so any slack thread of the loosely concatenated first stitch will be drawn taut thus also tightening the first stitch. With this arrangement it is unnecessary to draw oil an extra length of upper thread at the end of each sewing operation to provide for forming the first stitch, as is done in my above-mentioned patent and there is no danger that the first stitch will he lost or dropped by the action of the take-up.

I claim.

1. In a sewing machine adapted to perform a predetermined sewing cycle and provided with a stop motion to bring it to rest at the end of said cycle, the con'ibinat-ion with stitcht'ormingmechanism, of atension to r the thread, normally-idle means rendered operative after the stitch-forming mechanism has come to rest to release the tension, a latch for maintaining said tension released, and means to release the latch after the first stitch has been formed in the next sewing cycle.

2. In a sewing machine adapted to perform a predetermined sewing cycle and having a stop motion for bringing it to rest at the end of said cycle, the combination with stitchtorming mechanism including a needle, needle-jogging mechanism, a tension for the thread, means to release the tension at the end of the sewing operation and to maintain said tension released until after the first stitch has been made in the succeeding sewing cycle, and means controlled by the needlejogging mechanism to restore the tension after said first stitch has been formed.

3. In a sewing machine adapted to perform a predetermined sewing cycle and then come to rest, the combination with a needle, of needle-jogging mechanism, a tension for the thread, means to release the tension when the machine is brought to rest, a latch for holding the tension released, and means to release the latch by the operation of the needle-jogging mechanism after the sewing operation is again begun.

4. In a sewing machine adapted to perform a predeterimned sewing cycle and having a stop motion to bring it to rest at the end of said cycle, the combination with stitchforming mechanism including a needle for manipulating the needle thread, of a tension for said thread, needle-jogging mechanism, means to release the tension on said needle thread when the machine comes to rest and to maintain said tension released while the machine is at rest, and means controlled by the needle-jogging mechanism to restore the tension when the machine is started,

5. In a sewing machine adapted to perform a predetermined sewing cycle and having a stop motion to bring it to the rest at the end of said cycle, the combination with stitch-forming mechanism including a needle for manipulating the needle thread, or a tension for said thread, needle-jogging mecha nism, tension-releasing means, a cam for actuating said means which is normally idle during the sewing cycle but which is rendered operative after the stitch-forming mechanism comes to rest, and means controlled by the needle-jogging mechanism to restore the tension when the machine is again started.

6. In a sewing machine adapted to perform a predetermined sewing cycle and then come to rest, the combination with stitch-forming mechanism including a needle, of a tension for the thread, means to release the tension when the machine comes to rest, a vibrating member controlling the position of the needle, and means actuated thereby to restore the tension when the machine is started.

7. In a sewing machine adapted to perform a predetermined sewing cycle and pro vided with a stop motion to bring it to rest at the end of said cycle, the combination with stitch-forming mechanism, of a tension for the thread, means rendered operative by the stop motion to release the tension after the stitch-forming mechanism has come to rest and to maintain said tension released until the sewing machine is again started, and means to cause the tension to be applied again after the first stitch has been formed.

8. In a sewing machine adapted to perform a predetermined sewing cycle and pro vided with a stop motion to bring it to rest at the end of said cycle, the combination with stitch-forn'ling mechanism, of a tension for the thread, means rendered operative by the stop motion to release the tension after the stitch-forming mechanism has been brought to rest by the stop motion, said means operating to maintain the tension released while the machine is at rest, and means rendered operative after the first stitch has been formed when the machine is again started to cause the tension to be applied.

9. In a sewing machine adapted to perform a predetermined sewing cycle and provided with a stop motion to bring it to rest atthe end of said cycle, the combination wit-h stitch-forming mechanism including a needle, of needle-jogging mechanism, a tension for the thread, means rendered operative by the stop motion to release said tension after the stitch-forming mechanism has been brought to rest by the stop motion, and means actuated by the needle-jogging mechanism to cause the tension to be applied when the machine is started.

10. In a sewing machine adapted to perform a predetermined sewing cycle and provided with a stop motion to bring it to rest at the end of said cycle, the combination with stitch-forming mechanism, of a tension for the thread, means associated with the stop motion to release the tension after the stitch-forming mechanism has come to rest and to maintain said tension released while the stitch-forming mechanism is at rest, and means to cause the tension to be again applied after the first stitch has been formed when the machine is started in operation again,

In testimony whereof, I have name to this specification.

AXEL F. OARLS'ON.

signed my 

